<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
        <input type="text" name="box" value="请输入" id="z">
        <script>
            var zobj = document.getElementById('z');
            console.log(z.nodeType)     //打印出来是1, 所以是元素节点
        </script>
</body>
</html>